Heh, well, the way I want to go out is in an epic, awesome explosion. (I'm not talking as in I blow myself up, but I die in some tragic explosion.) In that way, my body would either not be there or too mangled up to be identifiable.
Now, I might be 16, but being a Catholic, I'd love to be buried in a traditional casket 6' under. I'm not too comfortable with the thought of being cremated, for I believe the term is "Rest in Peace", not "Be a Centerpiece." When you're buried, there's little chance of something happening to your body, as it'll just naturally deteriorate underground, rather than accidentally get spilled by a little kid or pet.
If I were to get cremated, I'd hope to have some sort of urn in a cemetery if at all possible. I'd like to have some sort of permanent resting place, not something I deem absurd, like being tossed into the ocean, blasted into space, or placed on The Haunted Mansion at Walt Disney World. As awesome as the ring idea is, where the carbon in my body gets converted into a stone, I'm concerned that'd scare the living crap out of people. Freezing my body is never going to happen. If I'm dead, I'm dead; I have no intentions of coming back to this planet once I leave here.